package kim.artemis.rpc.core.util;

import kim.artemis.rpc.core.common.exception.ArtemisException;
import org.springframework.aop.framework.AdvisedSupport;
import org.springframework.aop.framework.AopProxy;
import org.springframework.aop.support.AopUtils;

import java.lang.reflect.Field;

/**
 * 代理工具类
 * @author Wq.
 */
public class ArtemisProxyUtils {

    /**
     * 获取代理后真实对象
     * @param proxy
     * @return
     * @throws Exception
     */
    public static Object getTarget(Object proxy) {
        if(!AopUtils.isAopProxy(proxy)) {
            // 不是代理对象
            return proxy;
        }
        try {
            if(AopUtils.isJdkDynamicProxy(proxy)) {
                // JdkDynamicProxy
                return getJdkDynamicProxyTargetObject(proxy);
            } else {
                //  CglibProxyT
                return getCglibProxyTargetObject(proxy);
            }
        } catch (Exception e) {
            throw new ArtemisException(e);
        }
    }



    private static Object getCglibProxyTargetObject(Object proxy) throws Exception {
        Field h = proxy.getClass().getDeclaredField("CGLIB$CALLBACK_0");
        h.setAccessible(true);
        Object dynamicAdvisedInterceptor = h.get(proxy);
        Field advised = dynamicAdvisedInterceptor.getClass().getDeclaredField("advised");
        advised.setAccessible(true);
        Object target = ((AdvisedSupport)advised.get(dynamicAdvisedInterceptor)).getTargetSource().getTarget();
        return target;
    }


    private static Object getJdkDynamicProxyTargetObject(Object proxy) throws Exception {
        Field h = proxy.getClass().getSuperclass().getDeclaredField("h");
        h.setAccessible(true);
        AopProxy aopProxy = (AopProxy) h.get(proxy);
        Field advised = aopProxy.getClass().getDeclaredField("advised");
        advised.setAccessible(true);
        Object target = ((AdvisedSupport)advised.get(aopProxy)).getTargetSource().getTarget();
        return target;
    }

}
